Anaplastic Lymphoma Kinase (ALK) is a cell membrane-spanning receptor tyrosine kinase, which belongs to the insulin receptor subfamily. The most abundant expression of ALK occurs in the neonatal brain, suggesting a possible role for ALK in brain development (Duyster, J. et al., Oncogene, 2001, 20, 5623-5637).
ALK is also implicated in the progression of certain tumors. For example, approximately sixty percent of anaplastic large cell lymphomas (ALCL) are associated with a chromosome mutation that generates a fusion protein consisting of nucleophosmin (NMP) and the intracellular domain of ALK. (Armitage, J. O. et al., Cancer: Principle and Practice of Oncology, 6th edition, 2001, 2256-2316; Kutok J. L. & Aster J. C., J. Clin. Oncol., 2002, 20, 3691-3702). This mutant protein, NMP-ALK, possesses a constitutively active tyrosine kinase domain that is responsible for its oncogenic property through activation of downstream effectors. (Falini, B. et al., Blood, 1999, 94, 3509-3515; Morris, S. W. et al., Brit. J. Haematol., 2001, 113, 275-295; Duyster et al.; Kutok & Aster). Experimental data have demonstrated that the aberrant expression of constitutively active ALK is directly implicated in the pathogenesis of ALCL and that inhibition of ALK can markedly impair the growth of ALK+ lymphoma cells (Kuefer, Mu et al. Blood, 1997, 90, 2901-2910; Bai, R. Y. et al., Mol. Cell. Biol., 1998, 18, 6951-6961; Bai, R. Y. et al., Blood, 2000, 96, 4319-4327; Ergin, M. et al., Exp. Hematol., 2001, 29, 1082-1090; Slupianek, A. et al., Cancer Res., 2001, 61, 2194-2199; Turturro, F. et al., Clin. Cancer Res., 2002, 8, 240-245). The constitutively activated chimeric ALK has also been demonstrated in about 60% of inflammatory myofibroblastic tumors (IMTs), a slow-growing sarcoma that mainly affects children and young adults. (Lawrence, B. et al., Am. J. Pathol., 2000, 157, 377-384; Duyster et al.).
In addition, ALK and its putative ligand, pleiotrophin, are overexpressed in human glioblastomas (Stoica, G. et al., J. Biol. Chem., 2001, 276, 16772-16779). In mouse studies, depletion of ALK reduced glioblastoma tumor growth and prolonged animal survival (Powers, C. et al., J. Biol. Chem., 2002, 277, 14153-14158; Mentlein, R. et al, J. Neurochem., 2002, 83, 747-753).
It is possible that an ALK inhibitor would either permit durable cures when combined with current chemotherapy for ALCL, IMT, or glioblastoma, or be used as a single therapeutic agent in a maintenance role to prevent cancer recurrence in those patients. Various ALK inhibitors have been reported, including indazoloisoquinolines (WO 2005/009389), thiazole amides and oxazole amides (WO 2005/097765), pyrrolopyrimidines (WO 2005080393), and pyrimidinediamines (WO 2005/016894).
c-Met is a member of the tyrosine kinase growth factor receptor family. c-Met expression occurs in endothelial, epithelial, and mesenchymal cells. c-Met binding to the endogenous ligand, hepatocyte growth factor (HGF), promotes cell migration, proliferation, and invasion.
c-Met is implicated in the progression of certain tumors. c-Met overexpression has been shown in numerous tumor types including colon, breast, renal, lung, hemangiomas, squamous cell myeloid leukemia, melanomas, glioblastomas, and astrocytomas. (Maulik et al., Cytokine & Growth Factor Reviews, 2002, 13, 41-59; Funakoshi et al., Clinica Chimica Acta, 2003, 1-23; Longati et al., Curr. Drug Targets, 2001, 2, 41-55). Activation of tumor cell c-Met receptors enhances tumor cell proliferation, invasion/metastasis, and resistance to apoptosis and cytotoxic therapies.
It is possible that a c-Met inhibitor would have potent anti-tumor effects in many cancers. Various c-Met inhibitors have been reported, including aminoheteroaryl compounds (WO 2004/076412; WO 2005/082411; US 2005/0009840), 5-6 bicyclic heterocycles (WO 2005/028475), monocyclic heterocycles (US 2005/0245530), bicyclic heterocycles (US 2005/0239820), triazolotriazine compounds (WO 2005/010005; US 2005/0075340), triarylimidazoles (US 2005/0085473), indolinone hydrazides (WO 2005/005378), tetracyclic compounds (WO 2005/004808), imidazole derivatives (WO 2005/040154), quinolines and quinazolines (WO 2005/030140), and quinolinoxynaphthalenes (WO 2005/070891). (See also Sattler, M., et al., Cancer Res., 2003, 63, 5462-5469; Christensen, J. G., et al., Cancer Res., 2003, 63, 7345-7355).
A need exists for ALK and c-Met inhibitors for use as pharmaceutical agents.